Multiple Analyte Sensing and Molecular Computation with Luminescent Quantum Dots.

Being able to understand how cellular processes differ in normal and diseased states has enabled the development of therapeutic targets for a range of illnesses. Central to this understanding is the ability of sensors to permit the accurate determination of physiologically relevant analytes. Mostly, these sensors are based on fluorescence, a process where a molecule or object absorbs energy and then emits it in the form of light. Usually these sensors use organic dyes, similar to those used in paints as the light emitting unit. Using these systems, it is possible to only measure one analyte in real time, which can be a drawback as many diseases result in abnormal concentrations of more than one analyte, often with synergistic interactions.A new class of fluorescent molecules have recently been discovered and are called Quantum Dots. These molecules hold much promise as they have superior optical properties over organic dyes. These advanced properties mean that it is potentially possible to measure more than one analyte at the same time. We aim to make Quantum Dot probes for potassium, sodium and calcium ions with three different emission colours that will report on the concentration of these ions by the intensity changes of their fluorescence. This should permit the visualisation of these ions together in real time.In addition, as Quantum Dots are essentially the same type of materials as those used in information technology systems (semiconductors), we aim to show for the first time that it is possible to perform the logic operations with quantum dots. As they are much smaller than the currently used technology, they could be a new avenue to even smaller, faster devices.